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Finding the Fourth Proportional to 840.87, 1,261.37 and 255.92

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Solution

The fourth proportional to 840.87, 1,261.37 and 255.92 is: 383.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.87 : 1,261.37 = 255.92 : x
  2. Step 2: Convert to fraction form
    840.87/1,261.37 = 255.92/x
  3. Step 3: Cross multiply
    840.87x = 1,261.37 × 255.92
  4. Step 4: Simplify right side
    840.87x = 322,809.81
  5. Step 5: Solve for x
    x = 322,809.81/840.87
  6. Step 6: Final answer
    x = 383.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.